As semiconductor devices continue to decrease in size and increase in density, a primary challenge relates to reduction of electromagnetic (EM) and radio frequency (RF) interference, or other inter-device interference which can adversely affect the operation and performance of neighboring devices. EM and RF interference is the undesired electrical or radio signals or noise in the electronic system circuitry of a device caused by the unintentional coupling of EM or RF field energy from external sources. Such external sources include, for example, wires, printed circuit board conductors, connector elements and pins, cables, and other circuitry of nearby devices.
For semiconductor packages used in wireless systems, a shield may be used to protect the electronics of the device from unintended EM or RF energy. The shield also functions to prevent unintended radiation of EM energy from the electronics of the device to other circuitry.
Various attempts have been made to shield semiconductor packages from undesirable EM or RF interferences by applying a shielding layer over the encapsulated device package with the shielding layer connected to ground using a grounding wire or external connection. However, such techniques increase the cost and complexity of the packaging process. In addition, there is no known shielding technique that can be applied universally to a variety of device package types, and that is also reliable and cost effective.